A nutritional myopathy enzootic in a group of yearling beef cattle.

Steers and bulls under feedlot conditions and on an apparently adequate ration developed transitory signs of diarrhea and unthriftiness. One animal became recumbent. Sick and clinically normal animals in the group had elevated serum creatine kinase and aspartate aminotransferase enzyme values and degenerative changes in muscle fibers on biopsy. Feed analysis was carried out and the animals were monitored over several weeks by means of muscle biopsy and serum enzyme analysis as well as by postmortem examination at slaughter. Subclinical myopathy was found in several animals and was thought to be related to low vitamin E content in the high moisture corn ration.